4. GROUND CLEARANCE
The Ground Clearance of a vehicle measured from a horizontal road surface to any point on the underside of the vehicle except the tyres, wheels, wheel hubs and brake backing plates shall, with the vehicle in its loaded state as specified by the manufacturer, be not less than:
for any point in the width of the vehicle which is within one metre fore and aft of any axle, 100 mm;
for the mid-point between any two consecutive axles, the dimension in millimetres obtained by multiplying the distance between those two axles in metres by 33.33.
http://www.vicroads.vic.gov.au/vrne/vrnint...04A171BCD2A5F8F
straight from the vicroads' mouth